The 11B(p,α)8Be → α + α and the 11B(α,α)11B Reactions at Energies Below 5.4 MeV

Measurements of the absolute cross section and angular distributions for the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{11} \hbox{B}(p,\alpha)^{8}{\text{Be}}\rightarrow\alpha+\alpha$$\end{document} and the 11B(α,α)11B reactions have been performed from 0.15 to 3.8 MeV for the 11B(p,α) study and from 2 to 5.4 MeV for the 11B(α,α) reaction. The absolute cross sections are presented in terms of the total number of α-particles detected in order to avoid uncertainties due to ambiguities in the number of alpha particles emitted in the reaction at a particular energy. The angular distributions of the 11B(p,α)8Be(2+) reaction were fit to a Legendre polynomial expansion and the coefficients are presented. Finally, the 11B(α,α)11B data were fit in terms of phase shifts (ignoring the spin of the target), providing a convenient representation of the elastic cross section data between 2 and 5.4 MeV.